wool to enable it to spin
easily. This oiling is generally known as wool batching, and before
the spun yarns or woven fabrics can be dyed it is necessary to remove
it.

Raw wool is a very impure substance, containing comparatively little
wool fibre, rarely more than 50 to 60 per cent. in the cleanest
fleeces, while it may be as low as 25 per cent. in the dirtiest.

First there is a small quantity of dirt; there is what is called the
suint, a kind of soapy matter, which can be removed by washing in hot
water. This soap has for its base potash, while its acids are numerous
and complex. The wool contains a fatty-like substance of the nature of
wax, called cholesterine, and this imparts to the fatty matter, which
be extracted from the wool fibre, very peculiar properties. Besides
these there are several other bodies of minor importance, all of which
have to be removed from the wool before it can be manufactured into
cloth.

Marker and Schulz give the following analysis of a good sample of (p. 016)
raw wool:--

Moisture 23.48 per cent.
Wool fat 7.17 "
Wool soap (suint), soluble in water 21.13 "
Soluble in alcohol 0.35 "
Soluble in ether 0.29 "
Soluble in dilute hydrochloric acid 1.45 "
Wool fibre 43.20 "
Dirt 2.93 "
------
100.00

Two principles underlie the methods which are in use for this purpose.
The first principle and the one on which the oldest method is based is
the abstraction of the whole of the grease, etc., from the wool by
means of an alkaline or soapy liquor at one operation. This cannot
nowadays be considered a scientific method. Although it extracts the
grease, etc., from the wool, and leaves the latter in a good condition
for after processes, yet with it one might almost say that the whole
of the soap or alkali used, as well as the wool grease itself, is lost
as a waste product; whereas any good process should aim at obtaining
the wool grease for use in some form or another. The second principle
which underlies all the most recent methods for extracting the grease
from the wool, consists in treating the fibre with some solvent like
benzol, carbon bisulphide, petroleum spirit, carbon tetrachloride,
etc., which dissolves out the cholesterine and any other free
fatty matter which is i